The present invention relates to a defoaming apparatus for use in a fermentation tank.
In chemical processes for producing acids, for example, for producing acids such as carboxylic acids using petroleum fraction as the starting material or feeding liquid, a large volume fermentation tank is employed. In this type of fermentation tank, the liquid in the tank is forcibly aerated by an agitating device such as rotary blades. However, because of the agitation and aeration, a large quantity of foams are produced which float on the liquid surface which degrades operational efficiencies of the process.
Conventionally, foams floating on the liquid surface have been broken and dispersed by employing rotary defoaming blades. However, no consideration was paid in the conventional devices to the relationship between the rotary speed of the defoaming blades and the agitation blades or the spiral stream produced due to agitation. To be more specific, according to the conventional defoaming apparatus, the agitation blades are rotated at a speed equal to that of the defoaming blades.